Common Pochard
Aythya ferina
The common pochard is a plump, medium-sized diving duck, measuring 42–49 cm (17–19 in) in length, with a wingspan of 72–82 cm (28–32 in). It is stocky and short-tailed, with a sloping forehead and relatively long bill. Its weight (which has been reported only for winter birds) ranges from 467 to 1,240 g (16.5 to 43.7 oz). Males average larger and heavier than females. Like most ducks, it is sexually dimorphic. The male has a chestnut-coloured head and neck, a black breast and tail, and a pale grey body, marked with fine vermiculations. Voice: The male is generally silent, though he may whistle softly as part of his courtship display. The female growls softly—a sound transcribed as krrr—if she is flushed. The duckling has a short contact call of two to four notes. If distressed, its calls are higher and faster than are those of Anas ducklings of the same size and age.
ID text from Wikipedia, CC BY-SA 4.0
Redhead
Aythya americana
The redhead is a pochard, a diving duck specially adapted to foraging underwater. Their legs are placed further back on the body, which makes walking on land difficult. The webbing on their feet is larger than dabbling ducks and their bills are broader to facilitate underwater foraging. In addition, pochards have a lobed hind toe. No pochard has a metallic colored speculum, something that is characteristic of other ducks. Voice: There is little information on redhead vocalizations outside of breeding calls. When the neck is fully extended in the neck-stretching display, males emit a cat-like wheee-oww. Males may also produce a soft coughing call, although this call is less frequent. Females emit a soft errrr note when inciting a male.
ID text from Wikipedia, CC BY-SA 4.0
Where you might meet both
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